Java收发邮件

た入场券 2023-10-07 09:06 151阅读 0赞

第一步对邮箱进行配置，以QQ邮箱为例,先在邮箱设置里面选择账户

![2020020709110014.png][]

然后开启服务，这一步需要短信验证，通过之后会生成授权码，记下来，一会有用

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2trazEwOUE_size_16_color_FFFFFF_t_70][]

第二步打开eclipse，建立项目，导入jar包，我用的jar包是mail-1.4.7.jar

收邮件代码如下：

import java.security.Security;
    import java.util.Date;
    import java.util.Properties;
    import javax.mail.Folder;
    import javax.mail.Message;
    import javax.mail.MessagingException;
    import javax.mail.NoSuchProviderException;
    import javax.mail.Session;
    import com.sun.mail.imap.IMAPFolder;
    import com.sun.mail.imap.IMAPStore;
    
    /**
     * 发送邮件
     * setRecipient(Message.RecipientType type , Address theAddress)、setRecipients(Message.RecipientType type , Address[] theAddress)、addRecipient(Message.RecipientType type , Address theAddress)、addRecipients(Message.RecipientType type,Address[] theAddress)方法都可以指定接受者类型，但是一般用后两个，这样可以避免意外的替换或者覆盖接受者名单。定义接受者类型：
     *Message.RecipientType.TO：消息接受者
     *Message.RecipientType.CC：消息抄送者
     *Message.RecipientType.BCC：匿名抄送接收者(其他接受者看不到这个接受者的姓名和地址)
     * @author rhy
     * @date 2018-7-23 下午3:11:05
     * @version V1.0
     */
    
    public class sendEmail {
    	public static void main(String[] args) {
            String host = "imap.qq.com";
            int port = 993;
            String username = "填写你的邮箱";
            String password = "填写你的密码或者开启服务时的授权码";
            final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory"; 
            Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
            Properties props = System.getProperties();  
            props.setProperty("mail.imap.socketFactory.class", SSL_FACTORY);  
            props.setProperty("mail.imap.socketFactory.port","993");  
            props.setProperty("mail.store.protocol","imap");    
            props.setProperty("mail.imap.host", host);    
            props.setProperty("mail.imap.port", "993");    
            props.setProperty("mail.imap.auth.login.disable", "true"); 
            Session session = Session.getDefaultInstance(props,null);  
            session.setDebug(false);  
            IMAPFolder folder= null;
            IMAPStore store=null;
            try {   
                store=(IMAPStore)session.getStore("imap");  // 使用imap会话机制，连接服务器
                store.connect(host,port,username,password);
                folder=(IMAPFolder)store.getFolder("Sent Messages"); //收件箱 
    
                Folder defaultFolder = store.getDefaultFolder(); 
                Folder[] allFolder = defaultFolder.list();
              for (int i = 0; i < allFolder.length; i++) {
                    System.out.println("这个是服务器中的文件夹="+allFolder[i].getFullName());
                }
                  // 使用只读方式打开收件箱 
                folder.open(Folder.READ_WRITE);
                int size = folder.getMessageCount();
                System.out.println("这里是打印的条数=="+size);
                Message[] mess=folder.getMessages();
              //  Message message = folder.getMessage(size);
                for (int i = 0; i <5; i++) {
                    String from = mess[i].getFrom()[0].toString();
                    String subject = mess[i].getSubject();
                    Date date = mess[i].getSentDate();
                    System.out.println("From: " + from);
                    System.out.println("Subject: " + subject);
                    System.out.println("Date: " + date);
                }
               /* String from = message.getFrom()[0].toString();
                String subject = message.getSubject();
                Date date = message.getSentDate();*/
               /* BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); */ 
    
            } catch (NoSuchProviderException e) {
                e.printStackTrace();
            } catch (MessagingException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (folder != null) {
                        folder.close(false);
                    }
                    if (store != null) {
                        store.close();
                    }
                } catch (MessagingException e) {
                    e.printStackTrace();
                }
            }
            System.out.println("接收完毕！");
        }
    }

发邮件（只是一个简单的发文本邮件的例子）：

import com.sun.mail.util.MailSSLSocketFactory;
    
    import javax.mail.*;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeMessage;
    import java.security.GeneralSecurityException;
    import java.util.Properties;
    
    public class sendEmails {
    
    	public static void main(String[] args) throws MessagingException, GeneralSecurityException {
            //创建一个配置文件并保存
            Properties properties = new Properties();
    
            properties.setProperty("mail.host","smtp.qq.com");
    
            properties.setProperty("mail.transport.protocol","smtp");
    
            properties.setProperty("mail.smtp.auth","true");
    
    
            //QQ存在一个特性设置SSL加密
            MailSSLSocketFactory sf = new MailSSLSocketFactory();
            sf.setTrustAllHosts(true);
            properties.put("mail.smtp.ssl.enable", "true");
            properties.put("mail.smtp.ssl.socketFactory", sf);
    
            //创建一个session对象
            Session session = Session.getDefaultInstance(properties, new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("你的邮箱","你的授权码");
                }
            });
    
            //开启debug模式
            session.setDebug(true);
    
            //获取连接对象
            Transport transport = session.getTransport();
    
            //连接服务器
            transport.connect("smtp.qq.com","你的邮箱","你的授权码");
    
            //创建邮件对象
            MimeMessage mimeMessage = new MimeMessage(session);
    
            //邮件发送人
            mimeMessage.setFrom(new InternetAddress("你的邮箱"));
    
            //邮件接收人
            mimeMessage.setRecipient(Message.RecipientType.TO,new InternetAddress("接收邮箱"));
    
            //邮件标题
            mimeMessage.setSubject("Hello Mail");
    
            //邮件内容
            mimeMessage.setContent("我的想法是把代码放进一个循环里","text/html;charset=UTF-8");
    
            //发送邮件
            transport.sendMessage(mimeMessage,mimeMessage.getAllRecipients());
    
            //关闭连接
            transport.close();
        }
    	
    }

可能出现的问题：报Access to default session denied

解决方法：

getDefaultInstance替换为getInstance

原代码：

Session session = Session.getDefaultInstance(properties, new Authenticator()

改为：

Session session = Session.getInstance(properties, new Authenticator()

原因：Session.getDefaultInstance()是获得一个默认的共享session

[2020020709110014.png]: https://img-blog.csdnimg.cn/2020020709110014.png
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